1. Field of the Invention
The present invention relates to a fusible link for preventing a current greater than a specified value from flowing into a circuit for a vehicle, for example.
2. Description of the Related Art
Conventionally, the power supply to a circuit in a vehicle from a battery is often conducted via a fusible link in order to prevent a current greater than a specified value from flowing into the circuit (see Japanese Patent Application Laid-open No. 2011-222189, for example).
In FIG. 4, one example of a fuse unit including a conventional fusible link is illustrated in three orthographic views. This fuse unit 7 illustrated in FIG. 4 is the one that is directly mounted on a rod-shaped electrode 82 projecting from a terminal mounting surface 81 of a battery 8, and includes a battery terminal 71 and a fusible link 72.
The battery terminal 71 is a terminal having a substantially rectangular shape in planar view, and on one end side in the longitudinal direction thereof, an electrode insertion hole 711 into which the rod-shaped electrode 82 of the battery 8 is inserted is provided. On the other end side in the longitudinal direction, a screw 712 to couple the battery terminal 71 and the fusible link 72 together is provided. The battery terminal 71 is connected to the rod-shaped electrode 82 of the battery 8 near the one end, and extends toward the other end toward an outer edge 81a of the terminal mounting surface 81.
The fusible link 72 is formed with a power supply portion 721, two circuit terminals 722, and fuse elements 723 provided on a connection terminal 73 and housed inside a resin housing 724 composed of insulating resin material. In FIG. 5, illustrated is a structure object including the power supply portion, the two circuit terminals, and the fuse elements provided on the connection terminal in the fusible link illustrated in FIG. 4.
To the connection terminal 73, the battery terminal 71 is connected. On this connection terminal 73, provided is an insertion hole 73a into which the screw 712 of the battery terminal 71 is inserted. The screw 712 inserted into this insertion hole 73a is fastened with a nut 713, and thereby the battery terminal 71 is connected to the connection terminal 73.
The power supply portion 721 is provided on the connection terminal 73 in an integrated manner, and is supplied with the electrical power via the battery terminal 71 and the connection terminal 73.
On each of the two circuit terminals 722, a circuit that operates by the electrical power from the battery 8 is connected. On each circuit terminal 722, provided is a connection screw 722a to connect a round terminal and the like of an electrical wire constituting the circuit, for example. On the circuit terminal 722, formed is an insertion hole 722b into which this connection screw 722a is inserted. The circuit terminal 722 is housed inside the resin housing 724 in a state that the connection screw 722a is being inserted into the insertion hole 722b. 
The fuse element 723 is formed connecting the power supply portion 721 and each of the two circuit terminals 722 in a belt-like shape narrower in width than the power supply portion 721 and the circuit terminal 722. Into each of the circuit terminals 722, the current from the battery 8 flows from the power supply portion 721 via the fuse element 723. When a current equal to or greater than a threshold value flows, the fuse element 723 fuses, and thereby an excessive current is prevented from flowing into the circuit.
The fusible link 72, as in the foregoing, is formed with the power supply portion 721, the two circuit terminals 722, and the fuse elements 723 formed of conductive metal and provided on the connection terminal 73 and housed inside the resin housing 724 composed of insulating resin material. The resin housing 724 is formed by insert molding in which the power supply portion 721, the two circuit terminals 722, and the fuse elements 723 provided on the connection terminal 73 are covered with and fixed (being molded) by the insulating resin material, for example. The resin housing 724 including insulating resin material covers and fixes parts of the circuit terminals 722, the fuse elements 723, and the power supply portion 721 provided on the connection terminal 73, in a state that the respective connection surfaces of the connection terminal 73 and the circuit terminals 722 are exposed and windows 724a are provided such that the fusing of the fuse elements 723 is visible. On the window 724a for visible recognition of fusing, a transparent cover 725 is put on, and the fusing of the fuse element 723 is visible through this transparent cover 725.
In recent years, space-saving in vehicles has been progressed and spatial allowance in the periphery of a battery installed has been dwindling, and thus downsizing of a fusible link that tends to occupy the space near the rod-shaped electrode of the battery has been required.